Control device for a two section belt conveyor



United States Patent Inventor Walter Reist Hinwil, Zurich, Switzerland Appl. No. 731,856 Filed May 24, 1968 Patented Dec. 8, 1970 Assignee Ferag, Fehr & Reist AG Zurich, Switzerland Priority May 26, 1967 Switzerland No. 7465/67 CONTROL DEVICE FOR A TWO SECTION BELT CONVEYOR 7 Claims, 2 Drawing Figs.

U.S. Cl 198/76, 198/40 Int. Cl 865g 37/00 Field of Search 83/74, 72,

[56] References Cited UNITED STATES PATENTS 1,848,102 3/1932 Blair 198/37 2,345,355 3/1944 Neal 198/37 2,662,633 12/1953 Kings1ey.... 198/37 2,837,198 6/1958 Griffin 198/34 3,212,622 10/1965 Metz 198/40 Primary Examiner-Richard E. Aegerter Attorney- Waters, Roditi, Schwartz & Nissen ABSTRACT: A control device for a two-section belt conveyor particularly for transporting newspapers in a continuous imbricated or overlapping formation, comprises feeling device for detecting a gap in the continuous formation and an electric control circuit including switching means actuated upon detection of a gap in the continuous formation for stopping the leading portion of the continuous formation until the gap has been filled up by the continuously advancing lagging portion of the continuous formation.

CONTROL DEVICE FOR A TWO SECTION BELT CONVEYOR The invention relates to a control device for a two-section belt conveyor for maintaining a gapless conveying sequence of articles aligned in imbricated formation, particularly newspapers.

With articles transported in imbricated formation on conveyor belts to processing stations, it is mostly required, in order to obtain a regular and undisturbed operation, that no gaps or interruptions occur in the imbricated sequence. This gapless imbricated sequence is particularly important with newspapers, for example in a package laying-out device which piles up newspapers supplied in imbricated arrangement to packages. Usually, a package laying-out device comprises an incoming belt having its own drive, on which newspapers from the delivery station are deposited by a delivery belt. In the package laying-out device the incoming imbricated sequence is braked, causing the newspapers to slide one upon the other to a pile. When an interruption is present in the imbricated sequence the last newspapers of the leading portion of the sequence will be braked in the package layout device, while the first newspaper in the lagging flow portion has the constant speed of the delivery belt. The two newspapers are telescoped one into the other and stoppages will occur, which must be removed prior to be able to continue piling. Such stoppings due to interruptions will occur in all places where an imbricated sequence is delivered by a faster travelling belt to a slower travelling belt. Since it is practically not possible, in an extensive transportation plant, to make all component belts travel at exactly the same speed, without complex means and considerable expense, .interruptions in the imbricated sequence cannot be avoided. Samples must be continuously taken away, for maintaining a gapless imbricated sequence in such transportation plants.

It is an object of the invention to provide a control device which supervises the continuity of an imbricated sequence and automatically removes occuring interruptions at the junction area between two successive conveyor belts.

' According to the invention, a feeling device is arranged at the junction area between two successive conveyor belts to detect interruptions in the imbricated arrangement, and a switching device .is interposed in the drive of that conveyor belt which is first in transporting direction, said switching device being controlled by the feeling device and being operative upon a detected interruption, to stop said first conveyor belt for a determined time, a step being provided in the level of the travelling path between the first and second conveyor belts, so that the beginning of the lagging portion of the imbricated sequence is pushed by the moving second belt onto the end of the leading portion of the imbricated sequence on the stopped first conveyor belt during its stopping period, until the gap in the imbricated sequence is filled up.

- The invention will be described hereinafter in detail with reference to an example of execution illustrated in the accompanying drawings.

FIG. 1 diagrammatically represents the junction areas between two conveyor belts with a gap detected by the feeler device in the imbricated sequence of newspapers;and

FIG. 2 diagrammatically represents the procedure of filling of the gap;

Of the diagrammatically represented conveyor belts in FIGv 1, the conveyor belt 1 which is the first in conveying direction shall be for example the incoming belt of a package laying-out device for newspapers, and the second conveyor belt 2 shall be the delivery belt of a receiving station. The driving shaft of the incoming belt 1 is coupled with the driving motor 4 by means of an electromagnetic coupling 3. The drive of the incoming belt I is so formed that upon disengagement the belt is stopped almost instantaneously. The two conveying belts I and 2 carry an imbricated formation of newspapers 5, which at a certain place presents a gap, and accordingly it is interrupted.' In FIG. 1, this interruption has just reached the junction area 6 between the two belts] and 2, the leading portion 7 of the imbricated sequence having its last newspaper 8 on the incoming belt 1, and the imbricated portion 9 lagging behind having its first newspaper It) on the delivery belt 2. Because of the interruption in the imbricated sequence, the first newspaper 10 of the lagging imbricated sequence portion 9 is lying flat on the conveyor band 2. A light barrier 11 having a light source 12 and a photoelectric cell 13 as a feeling device for detecting interruptions is arranged at the junction area 6 between the two conveyor belts 1 and 2. Light source 12 and photoelectric cell 13 are so aligned that the diaphragmmasked light beam 14, upon an interruption in the imbricated sequence, is received by the photoelectric cell 13 and is interrupted by the newspapers sliding through the junction area. When an interruption occurs, a signal will be emitted by the photoelectric cell 13. The photoelectric cell 13 is connected to a control circuit 15. The control circuit comprises output terminals 16 to which is connected the electromagnetic coupling 3 arranged in the drive of the incoming belt 1. When the control circuit 15 receives an input signal from the photoelectric cell 13, i.e., when the light barrier detects the beginning of an interruption in the imbricated sequence, then the control circuit 15 causes disengagement of the electromagnetic coupling 3 and the incoming belt 1 is stopped, while the delivery belt 2 continues to move and conveys the lagging portion of the imbricated sequence further on. When the first newspaper 10 of this portion arrives at the junction area 6 scanned by the light barrier 11, the light beam 14 is interrupted by this newspaper. Without the provision of special expedients the electromagnetic coupling would now be engaged and accordingly the incoming belt set in motion again, without the desired gapless imbricated sequence having been attained. In order to avoid an untimely reengagement of coupling, this reengagement is made independent of the disappearing input signal in the control circuit 15. Different means are possible for obtaining this. For example, the procedure of filling the gap in the imbricated sequence could be supervised by a second light barrier which effects engagement of the coupling when the first newspaper 10 of the lagging portion 9 of the imbricated sequence has been pushed in correct positiononto the last newspaper 8 of the leading portion 7 of the imbricated sequence. Such or similar means, however, is relatively expensive, but has the advantage that it is independent of the speed of the delivery belt 2, the width of the existing gap and the breadth of the folded newspapers. In fact, the incoming belt 1 must be stopped for a determined time dependent on these three factors. The reengagement of the electromagnetic coupling 3 accordingly can also be effected directly by a determination of time, and for this purpose the control circuit 15 contains a time member. Since in the practical operation, at least for a prolonged time, the travelling speed of the delivery belt is sufficiently constant, and the width of the folded newspapers does not vary, it is sufficient in most cases, for the time switch existing in the control circuit 15 to be actuated by the scanning light barrier 11, upon disappearance of the signal, i.e., at the moment when the light beam is intercepted by the newspaper 10. After expiration of the adjusted time the newspaper 10 is correctly positioned on the newspaper 8, and the time switch engages the electromagnetic coupling 3. The means which shall be used for reengagement of the coupling 3 depend on the prevailing conditions and precision requirements. With high speed machines it is convenient to use a digital time switch.

In order for the first newspaper 10 of the lagging portion of the imbricated sequence 9 to pass upon the last newspaper 8 of the leading portion 7 of the imbricated sequence without disturbing the imbricated arrangement, a step 17 is provided in the level of the travelling path of the first and second conveyor belts. In the most simple case, as shown in FIG. I, the second conveyor belt 2 is disposed slightly higher than the first conveyor belt 1. Instead of this fixedly arranged step, an adjustable ramp can be provided with the second conveyor belt, which ramp easily adapts to the thickness of the newspapers, or generally to the articles transported. When an even level is required for transporting a homogeneous imbricated formation, this ramp can be made movable, its actuation being controlled by the control circuitin such manner that the ramp, upon disengagement of the electromagnetic coupling, is turned up and upon reengagement of the coupling is retracted to its original position.

FIG. 2 shows diagrammatically the imbricated succession with the filled up interruption. The light beam 14 of the light barrier 11 is interrupted by the newspapers 5 and both conveyor belts, the incoming belt and the delivery belt travel with approximately the same speed. When again an interruption occurs in the imbricated sequence the above described operation is repeated: The light barrier 11 responds and effects the stopping of the incoming belt 1, the delivery belt 2 continues the conveying of the imbricated sequence and pushes the lagging portion of the imbricated sequence on the resting portion 8 of the imbricated sequence, the first newspaper 10 interrupting the signal upon arriving at the light barrier and due to this interruption the coupling is reengaged after a certain time delay. Instead of the light barrier, obviously other suitable feelers could be used, for example a mechanical feeler actuated by the imbricated formation, which feeler actuates an electric contact when agap occurs in the imbricated sequence. Moreover, it is. not necessary that the incoming belt alone be stopped by means of the coupling, but the whole package laying-out device can be stopped by disconnecting the drive. The control circuit then does not actuate a coupling, for example a contactor. The formation of the control circuit is dependent on the type of feeler device used. For light barriers, generally an amplifier will have to be included in the control circuit.

Iclaim:

1. An apparatus for conveying articles comprising first and second conveyor belts, each adapted for transporting articles in imbricated relation, first and second drive means for driving respective belts, said first conveyor belt being adjacent said second belt for transferring articles in imbricated succession, sensing means for detecting any interruption in the imbricated succession of the articles before the articles are transferred to the second belt, and switching means coupling said sensing means with said second drive means for momentarily stopping said second drive means and said conveyor belt when said interruption in said imbricated succession of articles arrives between the first and second belts to cause said first conveyor belt to continue to deposit said articles on said conveyor belt and restore an uninterrupted imbricated succession of articles.

2. A control device according to claim 1 wherein said sensing means includes a light barrier.

3. An apparatus as claimed in claim 1 wherein said sensing means is positioned to detect interruptions in said imbricated succession as they arrive between the first and second belts.

4. An apparatus as claimed in claim 1 wherein said first conveyor belt is elevated relative to said second conveyor belt at the location where the articles are transferred from the first to the second belt.

5. An apparatus as claimed in claim 1 including timing means coupled with said sensing means for acting on said switching means to activate said second drive means after a predetermined period after restoration of an uninterrupted imbricated succession of articles, said restoration being detected by said sensing means to operate said timing means.

6. A control device according to claim 5 wherein said timing means is adjustable.

7. A control device according to claim 5 wherein said timing means is a digital time switch. 

